books.google.com - On the Origin of Species, published in 1859, is widely accepted as the seminal work in modern biology. Through careful observation, Charles Darwin explains how traits can be selected for within a population. This is easily observed in the artificial selection of farm animals, for instance. Darwin's theory...http://books.google.com/books/about/On_the_Origin_of_Species.html?id=bFXDg6-IxlcC&q=crustaceans&utm_source=gb-gplus-shareOn the Origin of Species